When you press the shutter release on a camera, there's usually a lag time or delay before the shutter actually fires. This corresponds to the time required for the autofocus and autoexposure mechanisms time to do their work, and can amount to a fairly long delay in some situations. Since this number is rarely reported on (and even more rarely reported accurately), and can significantly affect the picture taking experience, I routinely measure both shutter delay and shot to shot cycle times for all cameras I test, using a test system I designed and built for the purpose. (Crystal-controlled, with a resolution of 0.001 second.) Here are the numbers I collected for the Canon PowerShot S2IS. (Green-tinted cells highlight areas of notable improvement over the previous S1IS model.):

Canon PowerShot S2IS Timings

Operation

Time
(secs)

Notes

Power On -> First shot

1.5

LCD turns on and lens extends forward. Pretty fast for a camera with a telescoping lens.

Shutdown

1.6 - 2.6

First time is time to retract lens, second time is worst-case buffer-clearing time. Very fast, buffer clears almost immediately with a fast memory card.

Play to Record, first shot

1.0

Time until first shot is captured. A bit better than average speed.

Record to play

1.9 / 1.0

First time is that required to display a large/fine file immediately after capture, second time is that needed to display a large/fine file that has already been processed and stored on the memory card. Fairly fast.

Shutter lag, full autofocus

0.60 / 0.62

First time is at full wide-angle, second is full telephoto. Faster than average, particularly for a long-zoom model.

Shutter lag, continuous autofocus

0.62

As usual, no benefit for continuous AF with stationary subjects. (Might help with moving subjects, but we don't have a good objective test for that.)

Shutter lag, manual focus

0.45

On the slow side of average these days.

Shutter lag, prefocus

0.083

Time to capture, after half-pressing shutter button. Very fast.

Cycle Time, max/min resolution

1.51 / 1.44

First number is for large/fine files, second number is time for "TV" mode (640x480) images. Times are averages. In both modes, clears the buffer after each shot and maintains this pace indefinitely. Pretty fast, very impressive that there's no buffer limit. (Tested with a Lexar 32x SD card though, note that slower cards could well result in buffer limits.)

Cycle Time, Flash exposures

8

Flash at maximum power output. On the slow side of average.

Cycle Time, continuous High
mode, max/min resolution

0.44
(2.3 fps)

Shoots at the same speed for large/fine files or "TV" size images. Times are averages. In both modes, clears the buffer after each shot and maintains this pace indefinitely. (Tested with a Lexar 32x SD card though, note that slower cards could well result in buffer limits.) Very impressive for a consumer-level camera.

Cycle Time, continuous Low
mode, max/min resolution

0.68 / 0.67
(1.47 / 1.49 fps)

First number is for large/fine files, second number is time for small/basic images. Times are averages. In both modes, clears the buffer after each shot and maintains this pace indefinitely. (Tested with a Lexar 32x SD card though, note that slower cards could well result in buffer limits.) Also very good.

Good to very good shooting speed, several significant improvements over S1IS model. The Canon PowerShot S2IS is a pretty responsive camera, improving over the performance of its S1IS predecessor in startup/shutdown times, as well as autofocus, single-shot cycle times, and continuous-shooting speeds, even though the S2IS' files are considerably larger. Startup time is quite fast at only 1.5 seconds from power on to the first shot, a very good number for a camera with a telescoping lens. With a full-autofocus shutter delay of 0.60 - 0.62 second, the PowerShot S2IS focuses more quickly than most cameras on the market. (The S1IS had corresponding shutter lag numbers of 0.77 - 0.78 second.) In high-speed continuous mode, it really shines, able to shoot at 2.3 frames/second more or less indefinitely, until the card fills. (Note though, that this is likely only possible with a fast memory card, our tests here were performed with a Lexar 32x SD card. Slower cards are likely to encounter buffer-capacity limits.) All in all, a very responsive camera, particularly for a long-zoom model.

Power

The Canon PowerShot S2IS uses a four AA batteries for power, and ordinary
alkaline batteries are included with the camera. The table below shows the power
drain I measured in various operating modes, and the corresponding run times
to be expected from a standard set of 1600 mAh NiMH cells.

Operating Mode

Power
(@7.4 volts on the external power terminal)

Est. Minutes
(four 1600 mA cells)

Capture Mode, w/LCD

260 mA

239

Capture Mode, w/EVF

323 mA

193

Half-pressed shutter w/LCD

250 mA

249

Half-pressed w/EVF

312 mA

199

Memory Write (transient)

292 mA

n/a

Flash Recharge (transient)

792 mA

n/a

Image Playback

158 mA

393

Really excellent battery life. With a worst-case run time (capture mode, with the rear-panel LCD in use) of just under four hours, the Canon S2IS has much better than average battery life. In playback mode, run time stretches to a bit under 8 hours. (Note too, that these numbers are based on the "standard" 1600 mAh battery capacity that I've referred to since starting these measurements. Modern cells with true capacities of well over 2000 mAh would produce correspondingly longer run times.) Still, it's important to get high-capacity NiMH rechargeable AA cells and a good-quality charger. See my NiMH Battery Shootout page for actual test results for a wide range of cells currently on the market, and read my review of the Maha C-204W NiMH battery charger, to see why it's my current favorite.

Storage Capacity

The Canon PowerShot S2IS stores its photos on SD / MMC memory cards, and
a 16 MB card is included with the camera. (I strongly recommend buying
at least a 64 MB card, preferably a 128 MB one, to give yourself extra space
for extended outings.) The chart below shows how many images can be stored on
the included 32 MB card at each size/quality setting.

Image Capacity vs
Resolution/Quality
16 MB Memory Card

Fine

Normal

Basic

2592
x 1944

Images
(Avg size)

3
5.2 MB

5
2.9 MB

10
1.5 MB

Approx.
Compression

3:1

5:1

10:1

2048
x 1536

Images
(Avg size)

4
3.4 MB

8
1.9 MB

16
953 KB

Approx.
Compression

3:1

5:1

10:1

1600
x 1200

Images
(Avg size)

7
2.1 MB

13
1.2 MB

25
624 KB

Approx.
Compression

3:1

5:1

9:1

640 x 480

Images
(Avg size)

28
558 KB

44
361 KB

69
230 KB

Approx.
Compression

2:1

3:1

4:1

Download Speed

The Canon PowerShot S2IS connects to a host computer via a USB interface. Downloading files to my Sony desktop running Windows XP (Pentium IV, 2.4 GHz), I clocked it at 1673 KBytes/second, a very fast rate. (Cameras with slow USB interfaces run as low as 300 KB/s, cameras with fast v1.1 interfaces run as high as 600 KB/s. Cameras with USB v2.0 interfaces run as fast as several megabytes/second.)